Adjustable cam follower

ABSTRACT

A preferred form of follower includes an inverted cup-shaped body that fits over a valve stem of an overhead cam engine and includes a threaded central bore which receives a threaded plug. The bottom surface of the plug engages the valve stem and the top of the plug is provided with a square bore. A cap fits over the body and plug and is provided with a downwardly depending square boss that is fitted into the bore of the plug. The cap is provided with slots engageable by a screwdriver to rotate the cap and thus screw the plug axially inward or outward of the body to adjust the clearance between the cam and the valve stem. A plurality of circumferentially spaced locking holes are provided to be selectively engaged by a pin depending downwardly from the cap. A second form of the invention includes an inverted cupshaped body having an upwardly extending threaded boss. A cap overlies the body and is provided with a mating threaded bore. A recess is provided in the cap for rotating the cap and providing access to a set screw inserted through the cap for locking engagement with the threaded boss.

United States Patent [151 3,675,631 Hixson 1 July 11, 1972 [$4]ADJUSTABLE CAM FOLLOWER [72] Inventor: William J. Hixson, 4220 NE. 90thSt.,

Seattle, Wash. 98155 [22] Filed: June 3, 1970 [21] Appl. No.: 43,037

[52] U.S. C1 ..123/90.52, 123/9027, 74/55, 74/569, 74/586 [51] Int. Cl..F0ll l/20,Fl6h 53/06 [58] Field of Search ..123/90.27, 90.52; 74/55,569, 74/586 [56] References Cited UNITED STATES PATENTS 1,496,497 6/1924Swarthout et a1 ..l23/90.52 X 1,443,715 1/1923 Petaza ..l23/90.523,002,508 10/1961 Barker et al, ...................123190.27 X 1,746,8022/1930 Small .l23/90.52 X 3,002,509 10/1961 Fitzgerald et al. 1 23/90523,413,964 12/1968 Pask 123/9052 3,301,239 1/1967 Thauer.. ..l23/90.523,538,895 11/1970 Jensen ..123/90.27

Primary Examiner-Al Lawrence Smith Attorney-Seed, Berry & DowreyABSTRACT A preferred form of follower includes an inverted cup-shapedbody that fits over a valve stem of an overhead cam engine and includesa threaded central bore which receives a threaded plug. The bottomsurface of the plug engages the valve stem and the top of the plug isprovided with a square bore. A cap fits over the body and plug and isprovided with a downwardly depending square boss that is fitted into thebore of the plug. The cap is provided with slots engageable by ascrewdriver to rotate the cap and thus screw the plug axially inward oroutward of the body to adjust the clearance between the cam and thevalve stem. A plurality of circumferentially spaced locking holes areprovided to be selectively engaged by a pin depending downwardly fromthe cap. A second form of the invention includes an inverted cup-shapedbody having an upwardly extending threaded boss. A cap overlies the bodyand is provided with a mating threaded bore. A recess is provided in thecap for rotating the cap and providing access to a set screw insertedthrough the cap for locking engagement with the threaded boss.

6 Claims, 3 Drawing Figures P'A'TENTEDJuL n 1912 3.675.631

re in 7// A l l d WILLIAM J. HIXSON INVENTOR.

ATTORNEYS ADJUSTABLE CAM FOLLOWER BACKGROUND OF THE INVENTION 1 Field ofthe Invention This invention relates to cam followers of the typewherein the cam shaft is located directly over and in close proximity tothe valve stem.

2. Description of the Prior Art One difficulty imposed by the use ofoverhead type cam shafts is that the space available to make adjustmentsin the follower to provide proper valve clearance is very limited. Insome cases the follower is almost completely submerged in a sleeve or inthe engine head such that it is impossible to approach the follower fromthe side to make adjustments. One technique to solving this problem isto use special tools to make the adjustment and/or cut special bores inthe cam shaft to allow access to the follower from above the shaft, astaught, for example, in the patent to Thauer US. Pat. No. 3,301,239.Another technique has been to design the follower so that it extendsupwardly from the sleeve or engine head a sufficient distance to permitaccess with adjustment tools brought in from the side. Such a techniqueis shown, for example. in the patents to Fitzgerald et al. US. Pat. No.3,002,509 and Barker et al. US. Pat. No. 3,002,508.

SUMMARY OF THE INVENTION This invention pertains to an adjustable camfollower that may be approached directly from above when makingadjustments in the valve clearance. In the preferred form the followerincludes two members rotatable relative to one another and a thirdmember movable longitudinally of the first two members in response tosaid relative rotation. In this form of device the locking and adjustingoperation is accomplished within a space as narrow as 0.310 inches.Conventional tools, such as screwdrivers, may be used to make theadjustment and once made the first two members will automatically belocked together to prevent longitudinal movement of the third memberwhich would otherwise accidentally change the valve clearance setting.Since only three major parts are included the manufacturing andassembling costs are minimized. Furthermore, with this type of followerthe other parts of the engine, such as the cam shaft, need not havespecial features to allow for adjustment of the follower.

The second embodiment includes two members one threaded on the otherwhich may also be adjusted from above without the need of special tools.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an axial section of thepreferred form of adjustable follower of this invention.

FIG. 2 is a transverse section taken along the lines 2-2 of FIG. 1.

FIG. 3 is an axial section of the second form of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred embodiment, shownin FIGS. 1 and 2, cmploys an inverted cup-shaped body having dependingcylindrical side walls 12 and an upstanding peripheral shoulder 14. Thebody is provided with a central threaded bore 16 in which is received athreaded plug 18. The bottom surface of the plug is smooth and engagesthe top of a conventional valve stem 20. The top end of the plug isprovided with a square bore 24.

A cap 26 is seated in the recess within the peripheral shoulder 14 ofthe body 10 and is provided with a central, downwardly depending, squareboss 26 slidably engaged in the square bore 24. A locking pin 28 dependsdownwardly from the cap 26 and is engageable within one of a pluralityof circumferentially spaced locking holes 30 in the top surface of thebody 10. A plurality of notches 32 each having inclined top and bottomwalls are provided in the top surface of a cap 26. The notches are of asize suitable for penetration by the tip of a screwdriver so that thecap may be lifted and rotated. The length of the square boss 26 isgreater than that of the pin 28. Thus the cap may be raised to disengagethe pin from a locking hole 30 to permit relative rotation between thecap and the body while still maintaining contact between the square boss26 and the square bore 24.

To operate the cam follower of the preferred embodiment the shoulder 14of the body 10 is pressed downwardly to release the cap from engagementwith the cam shaft. Next, a screwdriver is placed in one of the notches32 and the cap is lifted to disengage the locking pin 28 from thelocking hole 30. Next, the cap is rotated and, since the square boss 26is still engaging the square bore 24, the plug 18 is screwed to moveaxially relative to the cap and body. Downward axial move ment of theplug decreases the clearance whereas upward movement of the plugincreases the clearance. The cam is locked to the body by lowering thecap and inserting the locking pin into one of the locking holes on thecap.

In the modification shown in FIG. 3 the follower includes an invertedcup-shaped body 50 having a depending cylindrical side wall 52 and adownwardly depending boss 56 which engages the valve stem 58. The body50 also includes an upstanding threaded boss 58. A cap 60 fits over thebody 50 and includes a central threaded bore 62 which receives thethreaded boss 58. Thus relative rotation of the cap and body will causerelative axial movement between the two to provide for valve clearanceadjustment. The cap is also provided with a recess 64 which terminatesin an inclined threaded bore 68 that intersects the threaded bore 62. Aset screw 70 is threaded into the inclined bore 68 and when threadedinto engagement with the threads on the boss 58 will preclude relativerotation between the cap and the body.

In this form of follower the valve clearance adjustment is made byloosening the set screw 68 and then rotating the cap 60 relative to thebody 50 by using a screwdriver or the like in the recess 64. When thedesired clearance is obtained the set screw 70 is then screwed intoengagement with the threads on the boss 58.

While preferred nonlimited forms of the invention have been describedmodifications will be readily apparent to those skilled in the art.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

I. An adjustable cam follower comprising an inverted cupshaped body withan open end embracing a valve stem and having a threaded central bore; aplug threaded into said bore; a cap overlying said plug and said body;means slidably interconnecting said cap and plug for rotation of saidplug with said cap thereby raising or lowering said plug relative tosaid body while permitting relative axial movement between said cap andsaid plug; means for rotating said cap; and means for releasably lockingsaid cap and said body against relative rotation when in a normaloperating condition.

2. The follower defined by claim I wherein said slidable interconnectingmeans includes a square bore in said plug and a square boss on said capdepending into said square bore.

3. The follower defined by claim 2 wherein said releasable locking meansincludes at least one locking hole in said body and a locking pin onsaid cap, said boss being of a length sufficient to be engaged in saidsquare bore when said locking pin is disengaged from said locking holewhereby the cap and plug are rotatable together relative to said body bylifting said cap to disengage said locking pin.

4. The follower of claim 3 wherein said body includes a plurality ofcircumferentially spaced locking holes.

5. The follower defined by claim 1 wherein said cap includes a topsurface and said means for rotating said cap includes a plurality ofnotches each of which includes inclined top and bottom walls adapted tobe engaged by a tool for simultaneously lifting and rotating said cap.

6. The follower of claim 4 wherein said cap includes a top surface andsaid means for rotating said cap includes a plurality of notches each ofwhich includes inclined top and bottom walls adapted to be engaged by atool for simultaneously liftin; and rotating said cap.

I ll t III

1. An adjustable cam follower comprising an inverted cup-shaped bodywith an open end embracing a valve stem and having a threaded centralbore; a plug threaded into said bore; a cap overlying said plug and saidbody; means slidably interconnecting said cap and plug for rotation ofsaid plug with said cap thereby raising or lowering said plug relativeto said body while permitting relative axial movement between said capand said plug; means for rotating said cap; and means for releasablylocking said cap and said body against relative rotation when in anormal operating condition.
 2. The follower defined by claim 1 whereinsaid slidable interconnecting means includes a square bore in said plugand a square boss on said cap depending into said square bore.
 3. Thefollower defined by claim 2 wherein said releasable locking meansincludes at least one locking hole in said body and a locking pin onsaid cap, said boss being of a length sufficient to be engaged in saidsquare bore when said locking pin is disengaged from said locking holewhereby the cap and plug are rotatable together relative to said body bylifting said cap to disengage said locking pin.
 4. The follower of claim3 wherein said body includes a plurality of circumferentially spacedlocking holes.
 5. The follower defined by claim 1 wherein said capincludes a top surface and said means for rotating said cap includes aplurality of notches each of which includes inclined top and bottomwalls adapted to be engaged by a tool for simultaneously lifting androtating said cap.
 6. The follower of claim 4 wherein said cap includesa top surface and said means for rotating said cap includes a pluralityof notches each of which includes inclined top and bottom walls adaptedto be engaged by a tool for simultaneously lifting and rotating saidcap.